Device for power transmission for variable load ratios



March 1x9, 1940. RQ R. DE voRE 2,193,805

DEVICE Fon Pom Tmmsulsslon Fon VARIABLE LOAD RA'rIos' Filed June 50, 1938 Jr i' Z TJ .51535152 Z Ei a f5 /W H y 1 l `E j if@ .WWW

Patented 19, 1940 UNITED STATES DEVICE FOB POWER TRANSMISSION FOR VARIABLE LOAD RATIOS Ralph R. De Vore, Washington. D. C. AApplication June 30, 1938, Serial No. 216,749

2 Claims.

(Granted under the act nf March 3. 1883 amended April 30, 1928; 370 0. G. 757) 'I'his inventionv relates to hydraulic transmissions for transmitting mechanical power at torques and at speed ratios which may vary over a suitable range. In equipment of this general 5 class a pressure fluid such as oil may be utilized to control the relative rotation and travel of gears, usually of the impeller type, arranged to constitute a. pressure iiuid translating means when flow of the pressure uid is permitted, and

when flow of the pressure fluid is completely stopped power is then transmitted at torque and speed ratios which are substantially unity; These ratios may be varied by controlling the flow of pressure fluid. Frequently, pressure fluid used in this manner is subjected to conditions of operation speeds, which cause the uid to become heated to a degree rendering it unsatisfactory for further use without first cooling the fluid. It is also highly desirable that rotatable parts of this equipment be substantially in static and dynamic balance .and that means be provided to assure adequate control of the ow of pressure fluid for effecting the transmission of power at ratios which may vary over a.v suitable range by comparatively small increments.

The purposes of this invention are to improve the efficiency of a device of the class described and .toxprovide for attaining this. desirable ob.

jective by improvements in construction and relative arrangement of parts which are also adapted to assure adequate and eilicient cooling of pressure fluid before `reuse of the same; to provide for maintaining the transmission substantially in static and dynamic balance; and

also to provide for controlling theflow of pressure fluid so as to make it possible to transmit power at ratios which may vary over a given range by very small increments.

A feature of the invention resides in the presy sure iiuid circulatory system which includes a cooling chambery of relatively large capacity, preferably suiflcient. to contain more than half of the pressure fluid in the system. This cooling chamber may be, and preferably is, shaped to perform its mechanical functions efficiently and also to have a heat transfer surface, as an exterior surface, which is comparatively large for the capacity of the chamber.

Another feature of the invention resides in the-arrangement-of the gearing and other parts so that the device as a whole is substantially in static and dynamic balance.

Another feature resides in the valve means 58 for controlling lthe flow of pressure fluid in the such as heavy duty'and/or high` on shafts I1 and I8, respectively. These gears 90 circulatory system. This valve means is responsive to movements in substantially like increments for changing the lport or flow area in increments changing progressively in both the closing and opening directions of movement of'y 5 said valve means. This provides for finer adjustment and control of the flow of pressure fluid in the circulatory system.

The features of the invention are illustrated in the accompanying drawing, wherein: 10 Fig. 1 is a section along the longitudinal axis of a hydraulic transmission, this view being taken along the broken line I-I ofv Fig. 4;

Fig. 2 is a section along the line 2-2 of Fig. 4,I with certain movable Vparts in different relal5 tive positions than those shown in Fig. 1;

Fig. 3 is a section along the line 3-3 of Fig. l; Fig. 4 is a section along the line 4 4 of Fig. 1; and

Fig. 5 is a section along the line 5-5 of Fig. 1 20 wlththe attaching elements removed. f

The illustrated embodiment comprises a sun gear'III and orbit gears II and I2 symmetrically disposed about the sun gear and in enmeshment with the sun gear for transmitting power be- 2;A

tween aligned shaft sections I3 and Il. The sunr gear may be xedly mounted on shaft section I3 by means of a key I6, as shown in Fig. 3, and the orbit gears II and I2 may be rotatably mounted may be disposed in a housing comprising a casting I9l 1aving a ange comprising arcuate end.,` portions 2| and 22'disposed about the gears II and I2, respectively, and the side portions 23 and v24 extending between `thel arcuate portions 35 #silenciosas the. Sangean .lheshafts "H and Iii/,for "rotatably "suplii'tingfthoibit' gears may n be in theform of bolts extending through the vcasting I9 and through a cover plate or closure member 26 which may be secured to the ange 40 of thehousing by suitable yattaching elements such as bolts 21. The .shafts I'I and I8 may be secured against rotation in' any approved manner as by providing each of these shafts with a at or irregular surface (not shown) flt- 45 ting a complementary surface in the housing. Shafts I'I and I8 may' be provided with hexagonal or other suitable heads 28 and 29, respectively, and the other ends of these shaftsmay be fitted with nuts 3l and 32, respectively. 'I'he 50 nuts 3l and 32 are adaptable to engage the end plate 26 and, in this way, to assist in holding this closure-plate against the ange of the casting I9. The shaft section Il may also befixedly secured to the gear housing as by means of any suitable connection, here shown as a key 33, disposed between the shaft I4 and the closure plate 26.

The casting III may also be provided with a' centrally disposed hollow extension 34 which may be substantially cylindrical on its outer end portion. The hollow interior of this extension provides'. an axially extending passage 36 which diverges about a central bearing boss 31 for the shaft section I3, and leads to a discharge port 3l for gears III and II (Figs. 3 and 4), and also to a discharge port 39 for gears I0 and I2. The outer' end of -this extension may be closed and sealed about the shaft section I3 by means of a suitable packing 4I. The casting I0 may also be provided with suitable openings 42 and 43 (Fig. 4). which constitute the pressure fluid intake ports for gears Il! and II and `for gears I0 and I2, respectively. I

The cylindrical extension 34 may be provided with one or more series of ports, preferably with two series of ports 44 and 46, respectively, through which pressure fluid may circulate. Preferably, the ports of each of these series are spaced longitudinally along the passage 36 by having the ports 'of each series arranged in substantially helical paths which may be oppositely directed about this extension so that the ports of each series are disposed in paths extending substantially 180 degrees around opposite sides of this extension, as shown in Figs. l and 2. Preferably, the ports of each series vary progressively in area, the outermost port of each series, or the one fartherest to the right, as viewed in Fig. 1, having the largest flow area and the innermost port of each series, or the one fartherest to the left, as viewed in Fig. l, having the smallest flow area. 'I'he flow of pressure fluid through these ports may be controlled by a valve member 41 in the slidably mounted on the shaft section I3 byv means of a bearing sleeve 49 carried by the closed end of the valve member. Suitable means such as the spaced collars 5I and 52 may be formed on the outer end of the bearing sleeve to provide a circumferential groove or channel in which the forked ends or furcations 53 and 54 of a floating lever 56 may ride.

A casing 51 may be disposed about the extension 34 and valve member 41, and at its outer end (Figs. 1 and 2) this casing may be sealed in substantially fluid tight relation with respect to the bearing sleeve 49 in any suitable manner, as by means of a flange 58 carried by the casing and fitting about the sleeve, and a suitable packing 69 disposed about the bearing sleeve between the ange 58, and a retaining nut 60 which may have threaded engagement with the ange. This end of the casing may also be provided with a suitable vent (not shown). This casing may be substantially frusto-conical in form, having its larger end following the cylindrical contour of the closure plate 26 and abutting the inner surface of this plate. An annular rib 6I may. be secured about the plate 26 by means of attaching elements such as bolts 62 to provide a support for the larger end of the casing 51. This casing may be secured against the outersurface annular rib and in fluid tight relation therewith in any approved man'ner as by 'welding the casing to thisrib.

'I'he space enclosed by this casing, the housing comprising the casting I 9 and the closure plate 26, and the valve member 41 provide a cooling chamber C into which pressure fluid is adapted to be discharged directly from the ports of the series 44 and 46, respectively. This chamber forms a.

part of a pressure fluid circulatory system, comprising the intake ports 42 and 43, the space between the gears I0, II, and I2 and the flange of the housing, the passage 36 and the ports of the series 44 and 46. This chamber is adapted to contain the greater proportion, and preferably about 60 per cent of the pressure fluid in the circulatory system, although good results may be obtained when this chamber has capacity representing between 50 and 60 per cent, or more, of the total capacity of the circulatory system. 'I'he rather peculiar shape of this chamber gives it an exterior surface which has a comparatively large area for the capacity of the chamber. This exterior surface functions as a heat transfer surface which may be exposed to suitable cooling media, such as atmospheric air. As the exterior surface of the extension 34 is also cooled by fluid in the chamber C, it will be seen that this extension also serves to some extent as a heat transfer surface, and that fluid in the passage 36 is therefore in heat transfer relation with fluid'in chamber C. The substantially conical walls of the casing 56, as illustrated in Figs. 1 and 2, cause a-body of fluid such as oil to tend to work inwardly along these conical wall portions during operation due tothe centrifugal force of the rotating body of fluid. This reduces any tendency for leakage along the bearing sleeve 49 and also provides for maintaining the main body of pressure fluid in the cooling chamber about the valve ports of the series 44 and 46, respectively, and about the intake ports 42 and 43.

ing the closure plate 26, for example, with theily wheel. In this type of installation the shaft section I4 would be either the crank shaft of the engine or a shaft section connected to the crank shaft.

In operation of this power .transmitting unit the cooling chamber C and the circulatory system may be substantially filled with a suitable pressure fluid such as oil, and power may be transmitted in either direction between the shaft sections I3 and I4, through the gearing II), II, and

I2, and the gear housing comprising a casting I9 and closure plate 26. When the floating lever 56 is moved to the position shown in Fig. 2, the axially sliding valve member 41 is also moved to a position to close all of the ports of the series 44. and 46, respectively, except the smallest ports of each series. It will be understood that when the valve member 41 is moved farther to the left. as viewed in Fig. 2, so as to close all of the ports of the series 44 and 46, circulation of pressure fluid will be completely stopped and the gears I I and I2 will be effectively locked in engagement with the gear I0 and, therefore, the shaft sections I3 and I4 must rotate in unison. When the valve member 41 occupies the position shown in Fig. 2 and ports of each series are arranged substantially as illustrated, only the smallest ports of each series are uncovered and only a restricted flow of pressure fluid is permitted. This restricted flow permits the gears II and I2 to travel in an orbit relative to the gear I0, and

in so doing the gears II and I2 cooperate with the gear II) to function as a pressure fluid translatlng means or gear pump. As the slidable valve member 41 is moved in this manner to uncover additional ports, the flow of pressure fluid will become less restricted and travel of the gears Il and I2 in their orbit relative to the gear II) will become more rapid. When the valve member 41 nas been moved to the position indicated in dotted lines in Fig. 2, all of the ports of each series will have been uncovered and there will be full and substantially unrestricted flow of the pressure fluid through the circulatory system. This will permit the gears II and I2 to travel freely about the gear I0, and practically no power will vbe transmitted between the shaft sections I3 and When power is applied to the shaft section Il or to the gear housing to rotate this housing in a counter-clockwise direction, as viewed in Fig. 3, the gears I0, II and I2, and the housing will rotate in the directions indicated by the arrows when flow of pressure fluid is permitted.

From the foregoing it will be evident that the mechanical power ytransmitted between the shaft sections Il and Il and the torque and speed ratios may be varied progressively by moving the floating lever to bring the valve member I1 to a position in which it controls the flow to give practically any desired result. As the ports first uncovered by the valve member 41 in moving from its closed position may be, and preferably are, very small and succeeding ports may increase progressively in area, as shown, a very flne adjustment and accurate control of the pressure fluid, and hence, of the torque and speed ratios, are possible with this transmission. It will also be noted that the symmetrical arrangement of the gearing and other parts of this transmission about the axis of rotation provides a device which is inherently in static and dynamic balance, and is therefore substantially free from all unnecessary vibration and noise.

The invention describedV herein, if patented, may be manufactured and used by or for the Government for governmental purposes without the paymentto me of any royalty thereon.

What I .claim is:

1. A fluid pressure transmission of the class described, comprising-shaft sections, a sun gear of the impeller type fixed on one of said shaft sections, orbit gears of the impeller type cooperating` with said sun gear to provide a pressure uid impelllng means, means rotatable with the other of said shaft sections for supporting said orbit gears, a pressure fluid-circu1atory system comprising a fluid cooling chamber having a relatively large surface area exposed to atmospheric air, means for conducting pressure uid from the discharge sides of said gears to said chamber, means for conducting pressure fluid from said chamber to the intake sides of said gears,` valve means within said chamber for controlling the ow of pressure fluid between the discharge sides of said gears and said chamber, said valve means comprising cooperating telescopicallyarranged relatively fixed and substantially axially movable members within said chamber, one of these members having one or more series of ports, the ports of each of said one or more series decreasing progressively in area substantially from fully open to closed position of .said valve means so that said ports may be controlled in ing said orbit gears substantially in static and dynamic balance about said sun gear, a pressure fluid circulatory system comprising a fluid cool- -ing chamber havinga capacity to contain the greater proportion of pressure fluid in said system and having a relatively large surface area exposed to cooling media, means for conducting pressure fluid from said chamber to the intake sides of said gears. means within said chamber providing a substantially axially extending passage for conducting pressure fluid substantially from the discharge sides of said gears to said chamber, valve means substantially within said chamber for controlling the ow of pressure fluid between the discharge sides of said` gears and said chamber, said valve means comprising cooperating relatively fixed and substantially axially movable members, one of these members having one or more series .of ports, the ports of each of said one or more series decreasing progressively in flow area from fully open to closed position of said valve means, so that said ports may be controlled in succession.v

RALPH R. DE VORE. 

